The present invention relates generally to hand-held, manually-operated sanding tools that use a sheet of abrasive material such as sandpaper.
Abrasive sheets, such as conventional sandpaper, are commonly used to hand sand or finish a work surface, such as a wooden surface. In hand sanding, the user holds the sandpaper directly in his or her hand to move the sandpaper across the work surface. Sanding by hand can, or course, be an arduous task. To facilitate the hand sanding process, the sandpaper may be placed on a sanding block. Sanding blocks hold the sandpaper and can be readily grasped by a user to make hand sanding faster and easier. A commercially available sanding block is the 3M™ Rubber Sanding Block available from 3M Company, St. Paul, Minn.
Sanding blocks are known in the patented prior art. U.S. Pat. No. 5,168,672, for example, discloses an abrasive sheet holder having a base provided with clamping shoulders formed in a pair of opposed side edges thereof. A handle member is detachably secured over a rear surface of the base. The handle member has opposed flexible flange walls for clamping opposed end edge portions of an abrasive paper sheet which is positioned over a front working surface of the base with the edge portions of the paper sheet extending over the clamping shoulders.
U.S. Patent Application Publication No. 2003/0104777 discloses a sanding block including a generally rectangular base housing upon which a multi-contoured, generally convex hand grip is secured. The hand grip further defines inwardly extending concave portions that facilitate easy and secure grip by the user. An over-center lever clamp mechanism is operative at each end of the sanding block to secure the opposed ends of a sandpaper sheet in a releasable attachment.
Known sanding blocks suffer from one or more drawbacks or shortcomings. For example, tensioning the abrasive media is a desirable feature of sanding blocks. With known sanding blocks, however, it is often difficult to load the abrasive media and get it tight. If the media is not tight, it may wrinkle, and the wrinkles may snag on the work surface and cause the abrasive media to tear. In addition, wrinkles in the abrasive media may cause the work surface to be damaged or sanded unevenly.
Known sanding blocks may also require both ends of the abrasive sheet to be installed in the sanding block simultaneously, which can require considerable dexterity. Known sanding blocks also tend to be difficult and/or expensive to manufacture. Other sanding blocks may damage the abrasive sheet as it is installed on the tool, or may not optimally utilize the full sanding area of the abrasive sheet. There is, therefore, a need for a sanding block that is easy and inexpensive to manufacture, that can tension the abrasive sheet, that securely holds the abrasive sheet, is comfortable to use, and allows worn abrasive sheets to be quickly and easily replaced, and minimizes opportunity for user injury.
It would be desirable to provide a hand-held, manually-operated, sanding tool that securely holds, and is capable of tensioning, flexible flat sheets of abrasive material, such as conventional sandpaper, as well as resilient flexible abrasive sheets that are thicker than conventional sandpaper, such as the sheet-like abrasive materials described in, for example, U.S. Pat. No. 6,613,113 (Minick et al.). In addition, it would be desirable to provide such a sanding tool that can be manufactured easily and cost effectively, is comfortable to use, allows worn sheets to be quickly and easily replaced, and allows sheet-like abrasive materials to be secured tightly to the sanding tool without unnecessary slack and without damaging the abrasive sheet.